Abstract :
In the paper is presented a comparative analysis of some Tatar and Chuvash case affixes and are shown distinctions between both languages on morphemesemantic level. It mostly concerns the directive-dative case affix -GA, which is very widely used in Tatar, and the similar to it Chuvash directive-dative-accusative affix -NA, which is used more restrictively, so that they are similarly used only for directive-dative. In other samples, the sense, expressed in Tatar by the affix -GA, is expressed in Chuvash by possessive case affix -Ăn, by locative case affix -TA and by ablative case affix -TAn. Were investigated Tatar relative affix -DagI and Chuvash affix -Ti (a combination of locative affix -TA and prominent affix -i), which can be glued to a subjective more than once to form the so-called “recursive structures”. The definiteness category, present only in Chuvash, and expressed by prominence affixes (-i/-ě, -i, -xi, -sker), was investigated as well.